remove italics-related styling for quotations

This is intended to go with a96f157d7997d70eee1a223c26da0463187fab1d on
the branch of the same name in Aloha-Editor
Merge remote-tracking branch 'origin/58657378-boxes-and-spacing' into testing
Merge branch 'testing' of github.com:oerpub/github-bookeditor into testing